71023639 has 4 divisors (see below), whose sum is σ = 73472760. Its totient is φ = 68574520.

The previous prime is 71023633. The next prime is 71023649. The reversal of 71023639 is 93632017.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71023639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71023639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71023633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1224517 + ... + 1224574.

It is an arithmetic number, because the mean of its divisors is an integer number (18368190).

Almost surely, 2^71023639 is an apocalyptic number.

71023639 is a deficient number, since it is larger than the sum of its proper divisors (2449121).

71023639 is a wasteful number, since it uses less digits than its factorization.

71023639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2449120.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 71023639 is about 8427.5523730203. The cubic root of 71023639 is about 414.1277251439.

The spelling of 71023639 in words is "seventy-one million, twenty-three thousand, six hundred thirty-nine".